Biological explanations: genetic Theory

Question 1

Biological explanation

Answer 1

There is growing evidence that genes we inherit from our parents can play a key role in our personality and vulnerability to mental illnesses. This explanation states that schizophrenia is a genetic illness.

Question 2

A genetic break through

Answer 2

Researches from MIT and Harvard have recently identified a gene which they believe increase the risk of schz. After conducting studies in both humans and mice, research said c4, a new schz risk gene, appears to be involved in eliminating the connection between neurons - a process called synaptic pruning, which in human happens naturally in the teen years.
It is possible that inappropriate pruning of neural connections could lead to the development of schizophrenia, which would explain why schizophrenia symptoms often first appear during adolescence.

Question 3

C4 is far above other risks associated with schz

Answer 3

The site in chromosome 6 harbouring the gene C4 towers above other risk- associated areas on schizophrenias genomic skyline, marking its strongest known genetic influence. This new study is the first to explain how specific gene versions work biologically to confer schizophrenia risk.

Question 4

Monozygotic twins and Dizygotic

Answer 4

Identical twins are also known as monozygotic twins
Identical twin result from the fertilisation of a single egg that splits in two
Identical twins share all of their genes and are always of the same sex
Fraternal twins are know as dizygotic twins
Dz twins are a result of the fertilisation of two separate eggs during the same pregnancy
DZ twins share up to half of their genes and mat be the same sex or different.

Question 5

Twin studies

Answer 5

Usual consist of a comparison in the concordance rate between MZ and DZ twins
If schz is caused by genetics, then we could expect the concordance rate to be higher for MZ twins in comparisons to DZ twins, due to MZ twins sharing more genes.

Question 6

Gottesman

Answer 6

Found that the concordance rates for schizophrenia based European twin studies from 1963 to 1987 was higher for MZ twins (48%) that for DZ twins (17%)

Question 7

Joseph

Answer 7

Calculated that pooled data for all schizophrenia twin studies carried out prior to 2001 showed a concordance rate for MZ twins of 40.4% compared to only 7.4% of DZ twins.

Question 8

APA (1994)

Answer 8

Showed that if one identical twin is affected by schz, there is a 40-60% chance their twin will suffer too. This reduced to 17% in non-identical twins.

Question 9

O’donovan et al

Answer 9

Identified 108 specific locations in the human genome that are linked to schz. Therefore it is unlikely that the illness can be attributed to only 1 gene. The most likely explanation is that schizophrenia is polygenic.

Question 10

Nature - nurture

Answer 10

No explanation should ignore the interaction between these two elements. Whilst genes may predispose someone to schz, its life events that trigger it. This could explain why both may carry the genes but one MZ twins develops schz. Therefore, an issue with twin studies means that perhaps alternative explanations for schz need to be considered and a more eclectic explanation should be adopted.

Question 11

Reductionist

Answer 11

They focus on only biological factors which ignore the role of psychological, cultural or social factors. A diathesis stress model should be adopted.